Enter the options menu and select "Gameplay".
Hold D-pad Left + Left Analog-stick Right and press Start.
The "Codes" selection will now be unlocked at the options menu.
Enter MEGASTARS as a case-sensitive code to unlock the
Sega Sports, Visual Concepts, and Team 2K2 in exhibition
and street modes.
Enter DUOTONE as a case-sensitive code to have your player
in color with all other players in black and white.
Trash in the streets:
Enter SPRINGER as a case-sensitive code to see trash in
the streets. Note: This does not work in the gym.